[PATCH v2 06/17] staging: comedi: quatech_daqp_cs: fix daqp_ai_cancel()

[H Hartley Sweeten]

Make sure interrupts are disabled and the event flags are cleared when
the analog input async command is canceled.

Remove the unnecessary calls to stop any running conversions in the
(*insn_read) and (*do_cmd) functions. The comedi core will only call
these functions if the subdevice is not busy (it has already been
canceled).

Signed-off-by: H Hartley Sweeten <hsweeten at visionengravers.com>
Cc: Ian Abbott <abbotti at mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
---
 drivers/staging/comedi/drivers/quatech_daqp_cs.c | 20 ++++++++------------
 1 file changed, 8 insertions(+), 12 deletions(-)

diff --git a/drivers/staging/comedi/drivers/quatech_daqp_cs.c b/drivers/staging/comedi/drivers/quatech_daqp_cs.c
index dbb8ffc..f337833 100644
--- a/drivers/staging/comedi/drivers/quatech_daqp_cs.c
+++ b/drivers/staging/comedi/drivers/quatech_daqp_cs.c
@@ -152,19 +152,21 @@ static const struct comedi_lrange range_daqp_ai = {
 	}
 };
 
-/* Cancel a running acquisition */
-
-static int daqp_ai_cancel(struct comedi_device *dev, struct comedi_subdevice *s)
+static int daqp_ai_cancel(struct comedi_device *dev,
+			  struct comedi_subdevice *s)
 {
 	struct daqp_private *devpriv = dev->private;
 
 	if (devpriv->stop)
 		return -EIO;
 
+	/*
+	 * Stop any conversions, disable interrupts, and clear
+	 * the status event flags.
+	 */
 	outb(DAQP_COMMAND_STOP, dev->iobase + DAQP_COMMAND);
-
-	/* flush any linguring data in FIFO - superfluous here */
-	/* outb(DAQP_COMMAND_RSTF, dev->iobase+DAQP_COMMAND); */
+	outb(0, dev->iobase + DAQP_CONTROL);
+	inb(dev->iobase + DAQP_STATUS);
 
 	devpriv->interrupt_mode = semaphore;
 
@@ -282,9 +284,6 @@ static int daqp_ai_insn_read(struct comedi_device *dev,
 	if (devpriv->stop)
 		return -EIO;
 
-	/* Stop any running conversion */
-	daqp_ai_cancel(dev, s);
-
 	outb(0, dev->iobase + DAQP_AUX);
 
 	/* Program one scan list entry */
@@ -443,9 +442,6 @@ static int daqp_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
 	if (devpriv->stop)
 		return -EIO;
 
-	/* Stop any running conversion */
-	daqp_ai_cancel(dev, s);
-
 	outb(0, dev->iobase + DAQP_AUX);
 
 	/* Program pacer clock */
-- 
2.5.1